The "Kodachrome 1/4 stop" standard was my idea. Imagine a perfectly exposed Kodachrome/Ektachrome, and a 1/2 stop off one. Big difference. OK, I'll lower my standards. How about 1/3 stop? But I won't go to 1/2 stop, and certainly not 2/3 or a whole stop.
HT, what you're delving into is a bigger picture litmus test.. Many of us are gearheads that like old mechanical things and wish for them to function with precision because we like the engineering and physics.. The other half want photos and have no interest in blaming their tools and use things like shutters with empirical experience rather than testing and heavy duty math. How accurate a shutter should be perfectly divides these crowds.
My speed graphic is pretty consistent shot to shot, but it does vary consistently based on temperature and whether horizontal or vertical.
You may never get your way except for a very time consuming tailoring of speed cams on a lef shutter. I’ve never seen a shutter spec that had a single spec value across the entire speed range.Originally Posted by HT Finley
The "Kodachrome 1/4 stop" standard was my idea. Imagine a perfectly exposed Kodachrome/Ektachrome, and a 1/2 stop off one. Big difference. OK, I'll lower my standards. How about 1/3 stop? But I won't go to 1/2 stop, and certainly not 2/3 or a whole stop.
On the focal plane shutter I think you’d have to somehow design a spring that is perfect across its entire tensionnrange, but I’ve never personally met such a spring.
But I’m back to my first reaction... other than the sheer magnitude of the challenge and good feeling from success... why, from a practical standpoint?
JP... same with mine but I’m blessed with warm winters so I never see much climate-based variability. I think a lot of that is the shutter cloth stiffening in the cold.
Because I shot a perfectly exposed and developed negative last week, and am not happy with the idea I was just lucky that once. For all I know the shutter could be off by half a mile. I can't stand not knowing. Besides I already know I'm a good camera technician. I've build several perfect Hasselblads and KNEW they were perfect; better than the factory. did it, if their published specs were correct. I got them focusing within 1/8 inch at 3 feet and proved it. 'Bout drove myself to the institution doing it....
Got it.
My suggestion is that your shot a few more, varying the shutter tension and comparing the negs.
I think I already might have driven myself crazy jsut thinking about this.
I doubt that.
Giving up to learn to love the bomb is healthy... ;-)
Many films won't see the difference, but there's that voice in one's head that gets louder while pressing the shutter release, so if at least if the speeds are uniform/consistent (and in a variety of conditions), it's OK...
Now to the film tests!!!
Steve K
I'm sure I will be corrected if I'm wrong, but as far as speed graphics curtain shutters go, the service manual I gleaned from the dedicated site only stated that adjustment is made so the shutter just closes at the end of the "o" opening? I have three speeds plus an old Marion and thorton pickard focal plane. Don't know how it will fare but I am waiting for a Cam-Lite mini V2 to arrive, which uses a light beam, is said to accommodate most shutters, we will see.
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